Lakeville, which has added hundreds of senior housing units in recent years, has changed its zoning code to allow more to be built — now in commercial areas where they previously weren’t allowed.

The City Council recently approved the change, which applies only to assisted-living and memory-care facilities that provide a range of health care and other services for seniors. The new rules don’t apply to independent-living senior complexes, which still must be in residential zones.

The zoning change opens up a vast amount of territory in Lakeville previously off-limits to assisted-living and memory-care centers. The four commercial zones where they now will be permitted make up more than 900 acres, including the city’s central business district and a large area off Interstate 35 from 205th to 215th Streets.

Planning Director Daryl Morey pointed out that not all of the new area is vacant. Much of it is populated with stores, restaurants and a few offices. But he added that the new rule wouldn’t preclude occupied land from being redeveloped into a senior housing project.

“It certainly broadens the types of land choices that these [senior housing] developers have,” Morey said.

“Obviously there’s a need here in the city, and I’m very excited to see this as an opportunity in commercial districts,” Council Member Bart Davis said at the meeting where the council unanimously approved the change.

Lakeville isn’t the only community in the midst of a senior housing boom. A recent report by National Investment Center (NIC), a Washington, D.C.-based senior housing research firm, showed that the Twin Cities had added assisted-living units at a faster pace than the average for the nation’s 31 largest metro areas.

City planners began looking into the zoning revisions a few months ago after being contacted by a commercial landowner who was working with a senior housing firm interested in his property at County Road 46 and Kenyon Avenue.

Morey said the firm cited senior properties it had been involved with in commercial districts in Blaine, Maplewood, Hugo and Champlin.

It also pointed out that Lakeville allowed nursing homes in commercial districts, but that nursing homes have largely been replaced by assisted-living and memory-care facilities.

The Minnesota attorney general’s office defines a nursing home as “a facility that provides nursing care to people who are not sick enough to need hospital care but who are not able to remain at home.” It says an assisted-living facility generally combines housing, support services and some kind of health care that can be customized according to the residents’ needs.

“Assisted living is an emerging sector that wasn’t getting specific attention in [Lakeville’s] zoning,” said Don Maietta, a Twin Cities real estate broker who had been working with the landowner and consultants for the senior housing firm. Morey agreed that the new rules take care of some outdated language.

Maietta said his clients now have begun work on a preliminary site plan for their project, which could have about 40 assisted-living and memory care units. He said a plan could be ready to submit to the city by next spring.

Meanwhile, Morey said the changes could open up new options for other senior housing developers that have recently contacted the city.

It also could free up more land in residential zones for independent-living senior developments as well as other types of higher-density housing, including apartment buildings.

“That wasn’t part of our consideration in the new ordinance, but it is a logical conclusion,” Morey said.